Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

True Masses using RV data with Hipparcos and Gaia Astrometry

G. Piccinini, A. Petralia, A. Sozzetti, S. Benatti, D. Gandolfi, G. Micela

TL;DR

This work addresses the sin i degeneracy in radial velocity mass measurements by combining RV data with Hipparcos–Gaia proper motion anomalies to constrain orbital inclinations and true masses of long-period companions. It presents a joint RV+PMA modelling framework, validates it on benchmark systems, and reanalyzes eight targets previously studied with Gaia DR1 simulations, using Gaia DR3 data where available. The results reclassify several objects (e.g., HD 5388 b, HD 6718 b) toward planetary masses and reveal complexities from additional companions (HD 16760, 30 Ari B), while noting cases with limited constraint (HD 148427 b, HD 96127 b, HIP 65891 b). The study demonstrates the utility of combining Gaia astrometry with RVs and RUWE/sensitivity-curve checks for robust true-mass determinations, with implications for exoplanet demographics and formation scenarios; future work will extend to multi-planet systems and Gaia PMEX data.

Abstract

Long-period companions are detected and characterized thanks to long-baseline radial velocity surveys. Combining Doppler time-series with astrometry, and in particular with proper motion anomalies technique, it is possible to put strong constraints on their orbital inclination and true mass. This work aims to present a model that combines Hipparcos and Gaia astrometric data with radial velocity measurements to constrain the orbital inclinations and true masses of long-period companions. Additionally, we re-analyse a small sample of targets that have not yet been studied using this combined approach. This research leverages the simultaneous modelling of proper motion anomalies and radial velocities, in conjunction with an analysis of the sensitivity curve. This approach serves not only as a verification of the parameters but also as a means to acquire valuable insights into planetary systems. The new analyses reveal that some of the targets classified as brown dwarfs or small-mass stars have a planetary nature. HD 5388 b and HD 6718 b are likely planets. HD 141937 b is likely a planet, but the current dataset does not allow us to firmly constrain its true mass. HD 16760 b belongs to the brown dwarf regime and it has a probable second companion. 30 Ari B b falls within the stellar regime, but the presence of an additional stellar companion could compromise the reliability of the final results. For HD 148427 b, HD 96127 b and HIP 65891 b we determined a range for the orbital inclinations.

True Masses using RV data with Hipparcos and Gaia Astrometry

TL;DR

This work addresses the sin i degeneracy in radial velocity mass measurements by combining RV data with Hipparcos–Gaia proper motion anomalies to constrain orbital inclinations and true masses of long-period companions. It presents a joint RV+PMA modelling framework, validates it on benchmark systems, and reanalyzes eight targets previously studied with Gaia DR1 simulations, using Gaia DR3 data where available. The results reclassify several objects (e.g., HD 5388 b, HD 6718 b) toward planetary masses and reveal complexities from additional companions (HD 16760, 30 Ari B), while noting cases with limited constraint (HD 148427 b, HD 96127 b, HIP 65891 b). The study demonstrates the utility of combining Gaia astrometry with RVs and RUWE/sensitivity-curve checks for robust true-mass determinations, with implications for exoplanet demographics and formation scenarios; future work will extend to multi-planet systems and Gaia PMEX data.

Abstract

Long-period companions are detected and characterized thanks to long-baseline radial velocity surveys. Combining Doppler time-series with astrometry, and in particular with proper motion anomalies technique, it is possible to put strong constraints on their orbital inclination and true mass. This work aims to present a model that combines Hipparcos and Gaia astrometric data with radial velocity measurements to constrain the orbital inclinations and true masses of long-period companions. Additionally, we re-analyse a small sample of targets that have not yet been studied using this combined approach. This research leverages the simultaneous modelling of proper motion anomalies and radial velocities, in conjunction with an analysis of the sensitivity curve. This approach serves not only as a verification of the parameters but also as a means to acquire valuable insights into planetary systems. The new analyses reveal that some of the targets classified as brown dwarfs or small-mass stars have a planetary nature. HD 5388 b and HD 6718 b are likely planets. HD 141937 b is likely a planet, but the current dataset does not allow us to firmly constrain its true mass. HD 16760 b belongs to the brown dwarf regime and it has a probable second companion. 30 Ari B b falls within the stellar regime, but the presence of an additional stellar companion could compromise the reliability of the final results. For HD 148427 b, HD 96127 b and HIP 65891 b we determined a range for the orbital inclinations.
Paper Structure (20 sections, 6 equations, 27 figures, 17 tables)

This paper contains 20 sections, 6 equations, 27 figures, 17 tables.

Table of Contents

  1. Introduction
  2. Methods
  3. Proper motion anomaly
  4. Validation of the results: Sensitivity Curve and RUWE
  5. Validation
  6. GJ 463 b
  7. $\pi$ Men b
  8. HD 222237 b
  9. Results
  10. HD 5388 b
  11. HD 6718 b
  12. HD 16760 b
  13. 30 Ari B b
  14. HD 141937 b
  15. HD 148427 b
  16. ...and 5 more sections

Figures (27)

  • Figure 1: Sensitivity Curve for GJ 463 companion. The purple line is the sensitivity curve using GDR3 with its 1$\sigma$ level of confidence. The red cross represents the value obtained by sozzetti2023dynamical using GDR3; the green cross is the prograde value and the blue cross is the retrograde value we obtained with GDR3 in this work: the three values are compatible with the sensitivity curve.
  • Figure 2: Sensitivity Curve for $\pi$ Men companion. The red cross represents the value obtained by damasso2020precise using GDR2; the green and the blue crosses are the results we obtained with GDR3 in this work for the prograde and the retrograde solutions, respectively: the values stay over the sensitivity curve.
  • Figure 3: Sensitivity Curve for HD 222237 companion. The red cross represents the value obtained by xiao2024hd using GDR3; the green cross is the prograde value and the blue cross is the retrograde value we obtained with GDR3 in this work: the three values are compatible with the sensitivity curve.
  • Figure 4: Top: RV data and Keplerian function of HD 5388 system. Bottom: Residuals of the fitted orbit.
  • Figure 5: Sensitivity Curve for HD 5388 companion. The blue line is the sensitivity curve derived using GDR2 with its 1$\sigma$ level of confidence. The red cross represents the value obtained by kiefer2021determining using GASTON. The green cross represents the prograde value, while the blue cross corresponds to the retrograde value we obtained using GDR3 in this work: our results are compatible with the sensitivity curve.
  • ...and 22 more figures